"To reserve a space" means to save or hold a specific area or spot for a particular purpose or person so that it will be available for their use. Full definition
Although I love the finer things in life, a couple of good, low priced items are something every girl should reserve space for in her wardrobe. (prettyyellowthings.com)
Please note that we only have a certain amount of spots at each orientation, so you must reserve your space in advance. (pawmettolifeline.org)
No need to rush to reserve space on the beach, with 150 meters of sand, there's plenty of space for everyone. (wavecation.com)